Elastic fluid turbine



Nov. 14, 1944. H. KRAFT ELASTIC FLUID TURBINE Fil ed Aug. 20, 1943 Inve ntor: I Hans Kr ft,

His Attorney.

Patented Nov. 14, 1944 ELASTIC FLUID TURBINE Hans Kraft, Schenectady, N. Y., alslgnor to General Electric Company, asorporatlon of New York Application August 2t, 1943, Serial No. 499,369

Claims. (cl. ass-1s) i The presentinvention relates to elastic fluid turbines, more particularly to nozzle and diaphragm arrangements used in the low pressure P rt of such turbines, in which elastic fluid carries an increasing amount of moisture, such as water, in the case of steam turbines. A substantial part of the water or moisture is deposited on the nozzle partitions. The water flows slowly along the surfaces of the partitions and as it reaches the outlet edges of the partitions it is blown off and forced towards the buckets of the succeeding wheel. Water or like liquid impinging on the entrance edges of such buckets may cause erosion and gradual destruction of the Y bucket entrance edges with resultantlos in emciency of the turbine.

The object of my invention is to provide an improved construction and arrangement of elastic fluid turbines whereby the aforementioned difllculties are substantially reduced. This is acil held in a groove of the casing It. The construction so'far described is well known in the In order to remove water or the like moisture deposited on or flowing slowly along the surfaces of the partitions the latter are made hollow. In the present example each partition has a radial bore l'l formed within the entranceportion of the partition and a slot it extending from the bore ll through the exit 'edge portion is. The slot II is curved, conforming substantially to the curvatures of the convex and concave surfaces of the partition. The outer ends of the bore or channel I! of each partition communicates with a radial bore extending through the ring it and leading to an annular groove 2! formed in the casing II. The groove 2| is connected by a channel 22 to a pipe 22 leading to a condenser complished by an improved nozzle arrangement with hollow partitions forming slots opening along the surfaces, preferably the exit edges,- of the partitions and means for connecting the hollow partitions to a vacuum or a point of lower pressure. The suction thus produced forces the water deposited on the surfaces of the partitions along such surfaces into the slots, whence the water may be carried away to a suitable point, such as the condenser of the turbine or heating system for feed water or the like.

For a better understanding of what I believe to be novel and my invention attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing. I

In the accompanying drawing, Fig. 1 illustrates a sectional view, partly broken away, of an elastic fluid turbine embodying my invention; Fig. 2 is an enlarged detail view of Fig. 1; Fig. 3 is a section along line 2-3 of Fig. 2, Fig. 2 being a sectionalong lines 2-2 01' Fig. 3; Fig. 4 shows a modification of my invention; Fig. 5 is a section along line 5-5 of Fig. 4; Fig. 6 is another modiflcation of my invention, and Fig. '7 is a' section along line 1-1 of Fig. 6.

The turbine comprises a casing ID with a plurality or axially spaced diaphragms ii supported on the casing. The diaphragms are cooperatively associated with a rotor including a plurality of bucket wheels l2 secured to a shaft it. During operation, elastic fluid, such as steam or mercury vapor, is conducted to a diaphragm, whence it is directed into a bucket wheel which in turn discharges into a succeeding diaphragm.

are secured, preferably welded, to an outer ring 24 for receiving exhaust fluid from the turbine. In Fig. 1 of the drawing I have indicated a channel 22 and a pipe 22 in connection with the first diaphragm ll only. The annular grooves 2| around the other diaphragms are directly connected to a point of low pressure, in the present instance the exhaust conduit of the turbine, by means of radial channels 22a in the lower part of the turbine casing.

In a preferred embodiment the exit edges of the partitions are cut away on the convex side of the partitions to facilitate the flow of moisture from said convex surfaces into-the slots l8 or, from another viewpoint, the wall portion of each partition'forming its concave side is extended in the direction of flow of fluid from the nozzles in order to assure substantial draining of moisture from the convex wall portion of the partition into the slot i8.

The modification of my invention as shown in Figs. 4 and 5 has a turbine casing 26. A diaphragm or like nozzle member or section 21 is supported in a groove 28 of the casing 25. The diaphragm has a plurality of circumferentially spaced, hollow partitions 29. These partitions may be made from sheet material by a forming process. The exit portions 30 of the partition walls are spaced to form a slot 8| through which fluid may be conducted from the nozzle passages between the partitions into the hollow spaces within the partitions. The inner ends of the par- 31. A drain conduit 38 is fused to the casing II to receive fluid from the discharge channel 38. The-drain conduit 38 is connected to a point of pressure low enough to induce flow of fluid through the slots 3| into the hollow partitions The hollow space formed within at least some of the partitions ommunicates with the channel I4 through radial openings 39 in the channel member 33.

During operation, moisture or liquid flowing along the convex and concave surfaces of he partitions is drawn into the slots 3| in the partitions and discharged therefrom through the channel as, whence the fluid is conducted into the drain conduit 38.

I The elastic fluid turbine arrangement of Figs. 6 and '7 comprises a turbine casing 45 and a rotor at disposed within the casing and including a row of circumferentially spaced buckets 41 forming bucket passages between them. Elastic fluid is conducted to the bucket passages by a nozzle arrangement which includes a row of circumferentially-spa'ced partitions 48 attached to an outer ring or support, in the present instance directly secured to the casing 155. Each partition has an outer dovetailed base 49 engaging a corresponding dovetailed circumferential recess c in the casing 55. The inner ends of the partitions it are connected to a shroud or band 5|. The partitions are hollow. Each partition has an inner wall. 52 (Fig. '2), thus forming two separate chambers, spaces or cavities 53 and 54 connected through slots to the outer surfaces of the partition. The cavity 53 communicates through a slot 55 with the concave surface and the cavity 5 3 communicates through a slot 55 with the convex surface of the partition. The partition has,

The slots 55, 55 are spaced The slot 56 forming an a sharp exit edge. from the exit edge.

inlet to the cavity 54 is located at a greater distance from the exit edge than the slot 55. Thus, in this arrangement several chambers are formed inside a partition for receiving fluid from dif-- ferent points of the nozzle space. The surfaces of the partition ahead and beyond the slots 55,

56 may form smooth continuations. In some instances, however, it is desirable to assure some scoop action into one of the cavities. Thus, in the present instance an exit portion 51 of the concave blade surface is thickened in order to facilitate flow of fluid into the cavity 53 through the slot 55. This is especially important in case the pressure in the chamber53 is slightly greater than the pressure outside the partition near the entrance to slot 55. The scoop action causes some of the velocity energy of the fluid to be converted into pressure energy to overcome the slightly greater pressure in the cavity 53. In other instances it may be desirable to reduce the thickness of the blade portion adjacent the slot 56 or to increase the thickness of the blade portion ahead of the slot 55 as regards the direction of flow through the nozzles passage. The two cavities or chambers 53, 54 are connected to septhe invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Elastic fluid turbine comprising a casing, a plurality of diaphragms supported in the casing, a rotor having bucket wheels associated with the diaphragms, each diaphragm having a pinrality of circumferentially spaced partitions, an outer ring secured to the outer ends of the partitions, and means for removing moisture from the surfaces of the partitions comprising channels formed in the partitions and extending through the exit edges thereof and means to induce a suction in said channels to induce moisture on the partitions to enter said channels.

2. Elastic fluid turbine comprising a casing, a plurality of diaphragms supported on the casing, a rotor having bucket wheels associated with the diaphragms, each diaphragm having a plurality of circumferentially spaced partitions, an outer ring secured to the outer ends of the partitions, each partition forming a slot having an inlet extending through and along the exit edge of the partition, and means for connecting said slots to a point of pressure lower than that normally existing near the exit edge of the partition to drain liquid deposited on and flowing along the surfaces of the partitions.

3. Elastic fluid turbine comprising a casing, a plurality of diaphragms supported on the casing, a rotor having bucket wheels associated with the diaphragms, at least one diaphragm having a plurality of circumferentially spaced partitions, an outer ring secured to the outer ends of the partitions, each partition forming a slot having an inlet extending along the exit edge of the partition, and means including channels formed in the outer ring and the casing for connecting said slots to a point of pressure normally lower than that existing near the exit edges of the respective partitions.

4. Elastic fluid turbine having a casing and a diaphragm supported on the casing and comprising a plurality of circumferentially spaced partitions forming nozzle passages between them,

each partition being curved in the direction of flow and being convex on one side and concave on the other, means for removing moisture from the concave and convex surfaces of each partition, said means including a channel formed in each partition and extending through and along the exit edge of the partition, and means for connecting said channel to a point of pressure lower than that normally existing near said exit edge to induce a flow of moisture from said surfaces into said channel, the exit edge on the convex side of each partition being partly cut away to facilitate the flow of fluid from the convex surface into the channel.

5. In an elastic fluid turbine, a casing, a nozzle arrangement for conducting fluid to a bucket wheel disposed in the casing, said arrangement comprising a plurality of circumferentially 

